Dhw Tank Temperature Control Of The Vitotronic 300-K - Viessmann VITOTRONIC 300 Installation And Service Instructions Manual

Vitotronic 300, GW5B & MW1B Installation and Service

DHW Tank Temperature Control of the Vitotronic 300-K

Brief description
H The DHW tank temperature control is a constant
temperature control. This is the result of starting and
stopping the circulation pump for DHW tank heating.
The switching differential is ±2.5 K.
H When the DHW tank is heated, a set supply
temperature is specified that is 20 K higher than the set
DHW temperature (adjustable via coding address "60"
in the "DHW" group).
Functions
Time program
An automatic or an individual time program may be
selected for DHW heating and the DHW circulation pump.
Compared with the heating circuit heatup phase, DHW
heating starts 30 min. earlier in automatic mode.
The individual time program enables up to 4 time
phases per day to be set for DHW heating and the DHW
circulation pump for every day of the week.
All DHW tank heating sequences will be completed
independently of the time program.
In conjunction with coding address "7F" in the "General"
group
H Detached house Code
"7F:1":
– Automatic mode
The heating times for heating circuit 1 are applied to
systems with two or three heating circuits.
– Individual time program
The time phases for DHW heating and the DHW
circulation pump have the same effect on all heating
circuits.
H Apartment building
Code "7F:0":
– Automatic mode
For systems with two or three heating circuits, the
heating times for the relevant heating circuit will be
applied.
– Individual time program
The time phases for DHW heating and the DHW
circulation pump can be adjusted individually for each
heating circuit.
Priority control
H With priority control: (code "A2:2" in the "Heating
circuit..." group):
The set supply temperature is set to 32° F (0° C)
during DHW tank heating. The mixing valve closes
and the heating circuit pump is switched off.
H Without priority control:
The heating circuit control unit continues to operate
with the same set value.
Frost protection
The DHW tank will be heated to 68° F (20° C) if the
DHW temperature sinks below 41° F (5° C).
Auxiliary function for DHW heating
This function is activated by providing a second set DHW
temperature via coding address "58" in group "DHW"
and activating the fourth DHW phase for DHW heating.
Set DHW temperature
The set DHW temperature can be adjusted between 50
and 140° F (10 and 60° C).
The set value range can be extended to 203° F (95 ºC)
via coding address "56" in the "DHW" group.
The set default value of the programming unit and/or the
Vitotrol 300A remote control units can be allocated via
coding address "66" in the "DHW" group.
DHW circulation pump
This delivers hot water to the draw-off points at
adjustable times.
Four time phases can be selected at the control unit for
every day.
Auxiliary circuits
DHW heating in conjunction with the heating circuits
can be disabled or enabled by changing over the heating
program (see coding address "D5" in the "Heating circuit
..." group).
System with primary store system
The above functions also apply in conjunction with
primary store systems.
Set the following codes:
"55:3" in the "DHW" group; "4C:1", "4E":
2 in the "General" group.
System with solar control unit
A third set DHW temperature can be specified via coding
address "67" in the "DHW" group.
The DHW tank is only reheated by the boiler if the
temperature falls below this value.
Function Description
69